Giant Sequoias [wiki] (Sequoiadendron giganteum), which only grow in Sierra Nevada, California, are the world's biggest trees (in terms of volume). The biggest is General Sherman [wiki] in the Sequoia National Park - one behemoth of a tree at 275 feet m)
(CALIFORNIA) The General Grant tree is the largest giant sequoia (Sequoiadendron giganteum) in the General Grant Grove section of Kings Canyon National Park in California and the third largest tree in the world.
Giant redwood (Sequoiadendron giganteum) - leaves - December 2017
Ireland to Plant Largest Grove of Redwood Trees Outside of California
Giant sequoia (Sequoiadendron giganteum) illustration 1862; The Forest Trees of California; by Edward Vischer; Agnew and Deffebach; San Francisco; Courtesy of the California Academy of Sciences Library; R2015.0709.021